Printing telegraph apparatus



April 18, H RASSOWEZT AL I \4 PRINTI NG TELEGRAPH APPARATUS Filed Aug. 28, 1937 INVENTOR. HORST RASSOW BY WILLY SKAWRAN Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE PRINTING TELEGRAPH APPARATUS Germany Application August zs, 1931, Serial No. 161,360 In Germany August 31, 1936 I Claims.

The present invention relates to printing telegraph apparatus and more particularly to the receiving component of such apparatus.

The principal object of the invention is the provision of an arrangement for the rapid and efficient recording of character symbols.

A feature of the invention resides in a receiving system responsive to current impulses of diminutive value yet enabling the rapid and reliable recording of character symbols.

A further feature of the invention resides in a receiving system including a single electromagnet which serves the dual capacity of releasing the driving mechanism and operating the printing mechanism.

Theabove and other objects of the invention are accomplished as specifically applied to a receiving printer wherein the'character symbols are composed of individual printed lines by arranging an electromagnet to respond to the received impulses to release the driving portion of the receiving apparatus for rotation and to serve to control the action of the printing hammer which cooperates with the spiral of the printing wheel to print character symbols, and which is moved-mechanically after the driven portion is released for rotation to maintain a predetermined relationship with the printing wheel to minimize the energy required to energize the electromagnet for printing. Such an arrangement predetermines the length of stroke of the release arm and the printing hammer which makes possible very eflicient and reliable operation with an extremely low current strength. A more complete understanding of the invention may be had from the following description taken in conjunction with the accompanying drawing which illustrates the invention as applied to a printing telegraph receiver of the type shown in Patent No. 2,046,328 to E. E. Kleinschmidt et al., granted July 7, 1936.

Referring now to the drawing which shows diagrammatically and in exploded relationship the parts of a receiving printer embodying the features of the present invention, a receiving electromagnet 4 consisting of two windings 5 and 6 is shown with the winding 5 connected to a line conductor 1. Current is normally impressed on line conductor 1 at the transmitter located either 50 remotely or locally. However, under either location of the transmitter, current normally flows through winding 5 of the electromagnet, and consequently its armature 8 is attracted. Winding 8 is provided as a delay or retard winding and may be either short circulted or placed in a delay current circuit, whereupon it is possible to choose any advantageous delay period. The short circuit may also be accomplished through a contact controlled by the transmitter so that it exists for only a certain time interval; for ex- 5 ample, the time of the start pulse.

As indicated, the electromagnet 4 is normally energized by current impressed on line conductor 1 and further, armature 8 is in one of its attracted positions. In such position armature 8 10 being rotated about its pivot 9 against the action of a rectractile spring, the printing hammer which is formed at one extremity of armature 8 is held out of engagement with printing wheel H, which, as exemplified in the foregoing patent 5 to E. E. Kleinschmidt et al.,, carries on its periphery a spiral printing edge which may be made suitable for printing on a strip I2 through the use either of an inking wheel or a carbon strip or ribbon. Inasmuch as the method of inking the g0 spiral printing edge does not constitute a part of the present invention, the structure therefor has not been shown.

The receiving printer includes a driven shaft iii to which power is communicated from a con- 5 tinuously rotating motor, not shown, through a friction clutch, not shown. Secured to shaft l3 are a plurality of cams i l, [5, and I6. Cam [4, which may be referred to as a stop cam or stop lug, cooperates with a hook portion integral with 30 the armature 8 of electromagnet 4 to hold shaft I3 against rotation during the idle period of the receiving printer. When a start impulse is received or when current is removed from line conductor I, armature 8 is released and is rotated 5 by its retractile spring about its pivot 9 to a position where the hook portion is free of the stop cam or stop lug i4. Shaft I3 is then rotated by power communicated from the continuously rotating motor through the indicated friction 4o clutch.

Also secured to shaft iii are cams l5 and I6 which serve to limit the travel of armature 8. For releasing shaft i3, it is necessary that armature 8 have a predetermined travel, whereas for printing, such required travel is considerably less than in the case of the releasing operation. In order to achieve the principal object of the invention, the cams I5 and I6 serve to control the travel of armature 8 in its function to release shaft l3 for rotation and to print through the cooperation of printing hammer l0 with the spiral on the printing wheel Ii. Cam i5 cooperates with the right extremity, as shown in the drawing, of armature 8, and in its normal position limits the downward travel of armature 8, whereas cam i6 cooperates with pivoted lever I! normally under the tension of a spring l8 to limit the back travel of armature 8. The armature 8 and lever I! are so formed or shaped to produce the described cooperation with the respective cams l4, l and I6.

To effect release of shaft l3, it is necessary that the armature 8 travel a distance such as indicated by the numeral 28. The movement of armature 8 to effect release of shaft I3 is determined by the position of lever I! which, as previously noted, is under the control of cam l6. Likewise, the travel of armature 8 in a direction against the action of its retractile spring is determined by cam I5 which, when in a position removed from normal, allows armature 8 to be attracted through a distance corresponding to the distance indicated by the numeral 2| sumcient to effect printing on the tape or strip l2 in response to the energization of winding 5 of electromagnet 4. Consequently, in response to subsequent character impulses the distance through which the armature 8 against the action of its retractile spring must move to effect printing is materially reduced, which results in a corresponding reduction in the electrical energy required to produce the necessary movement of the printing edge through distance 2| and in an increase in speed of printing which is effected by the electrical impulses received following the initial deenergization of the electromagnet 4 to release shaft l3 for rotation.

Normally, current flows through winding 5 and armature 8 is attracted against the action of its retractile spring to hold the hook portion in the path of stop cam or stop lug l4. Shaft I3 is thus held against rotation. Upon the removal of current from the line or in response to the receipt of a start impulse, electromagnet l is deenergized and its armature 8 is moved by its retractile spring through a distance indicated by the numeral 20 or to a position in contact with one extremity of lever l1. Such movement is sufficient to remove the hook portion of armature 8 from engagement with the stop cam l4 and thereupon shaft i3 is released for rotation and is rotated by power communicated from a continuously rotating motor through a friction clutch. With the rotation of shaft 13, cams I5 and I6 are rotated. The contour of cam I5 is such as to allow movement of armature 8 in response to electrical impulses through a distance sufiicient to force the printing hammer l8 into printing relation with the spiral on the printing wheel ii, whereas cam l6 when in of!- normal position, moves lever I1 against the action of spring l8 to a position such that the separation between armature 8 and the one extremity of lever I1 is substantially reduced, so that the movement of the armature 8 from its unenersized position to its energized position or printing position is minimized. In other words, the cams l5 and I6 serve to control variably the stop positions of armature 8. In the case of cam IS. the stop position of armature 8 is determined directly by the contour of the cam. The unenergized position of armature 8 is determined by the position of lever I! which, during rotation of cam l6, will be moved about its pivot to force armature 8 closer to the pole faces of electromagnet 4.

From the foregoing description, it is apparent that the cam l8, through its lever l1, allows a longer stroke of armature 8 for effecting release of shaft l3. However, during printing operation in response to electrical impulses, the stroke or the movement of armature 8 is decreased corresponding to the contour of cam 18.

Following the recording of the last element of the character symbol, current may be impressed upon line conductor 1 to cause the prolonged energization of electromagnet 4 in timed relation to the rotation of shaft l8. Under such conditions, armature 8 will be in the position shown in the drawing, and the hook portion thereof will lie in the path of the stop cam or stop lug I 4. Shaft l3 will, under such conditions, be held against rotation.

The drawing shows the invention as embodied in a particular type of receiving printer. It is however, obvious that the invention may be embodied in other forms of receiving printers without departing from the spirit and scope of the present invention.

What is claimed is:

1. A printing telegraph receiver including an electromagnet responsive to signal impulses, an operating shaft, means for normally holding said shaft against rotation actuated upon the initial operation of said electromagnet, and means effective following the release of said shaft for establishing a condition to reduce the energy required to operate said electromagnet.

2. A printing telegraph receiver including an electromagnet responsive to signal impulses, an armature therefor, an operating shaft, means controlled by said armature for holding said shaft against rotation and actuated by the initial operation of said electromagnet, and means efl'ective depending upon the position of saidshaft for determining the travel of said armature for the printing operation.

3. A printing telegraph receiver including an electromagnet responsive to signal impulses, an operating shaft, means for normally holding said shaft against rotation, an armature for said electromagnet controlling said means, means for allowing an extended travel of said armature in response to a start impulse to release said shaft, and means for restricting the travel of said armature for the remainder of the signal period.

4. A printing telegraph receiver including an electromagnet responsive to signal impulses, an operating shaft, means for normally holding said shaft against rotation, an armature for said electromagnet controlling said means, means including a cam for allowing an extended travel of said armature in response to a start impulse to release said shaft, and another cam operated in timed relation with said specified cam for restricting the travel of said armature for the remainder of the signal period.

5. A printing telegraph receiver including a printing wheel, an electromagnet responsive to signal impulses, an operating shaft for driving said printing wheel, means for normally holding said shaft against rotation, an armature for said electromagnet controlling said means, means for allowing an extended travel of said armature in response to a start signal impulse to release said shaft and cause the rotation of said printing wheel, and means for restricting the travel of said armature during printing of the character from said rotating printing wheel.

6. A printing telegraph receiver including an electromagnet responsive to signal impulses, an operating shaft, means for normally holding said shaft against rotation, an armature for said electromagnet controlling said means, a stop for electromagnet controlling said means, a pivoted stop for allowing an extended travel of said armature in response to a start signal impulse to release said shaft, and a cam secured to said shaft and operated thereby for moving said pivoted stop closer to said armature thereby to restrict the travel of said armature for the operation of printing.

HORST RASSOW'.

WILLY SKAWRAN. 

